Hydrogen has been considered as an ideal energy carrier owing to its high combustion heat, abundant resource and zero pollutant. Development of hydrogen energy will play a positive effect on carbon peaking and carbon neutrality goals, while it requires high-capacity and low-cost functional hydrogen storage materials. La-Mg-Ni-based A2B7-type hydrogen storage alloys originated from La-Ni binary alloys have the advantages of high capacity, low raw material cost. Mg addition into \[A2B4\] sub-units in La-Ni binary alloys suppresses hydrogen introducing amorphization and strengthens the bulk structure. The capacity of La-Mg-Ni-based A2B7-type hydrogen storage alloys is as high as 1.80wt%, much higher than commercial AB5type alloys. The crystal structure of La-Mg-Ni-based A2B7-type hydrogen storage alloys is adjustable and usually influenced by elemental substitution and preparation techniques. Based on these above, this paper reviews the influence of elemental substitution and preparation techniques on phase structure and hydrogen storage properties of La-Mg-Ni-based A2B7-type hydrogen storage alloys and points out problems in alloy development. It is devoted to providing ideas and theoretical guidance for getting highperformance La-Mg-Ni-based A2B7-type hydrogen storage alloys.